1. Long-distance wireless transmission (up to 500 meters in open area, 10kbps baud rate in the air). 2. Operating frequency range (433 - 458.5MHz, up to 255 communication channels). Maximum 100mW (20dBm) transmit power (10 levels of power can be set). 3. Built-in MCU, use serial port to communicate with external devices. Send 31 bytes at a time. 4. The module supports one-to-one, one-to-many transparent transmission communication through ID setting. Changing the baud rate of a different serial port will synchronously change the rate at which data is sent over the air (10kbps-100kbps). 5. Set the 'critical three minutes'. The module can send and receive data normally within three minutes of power-on. You can send the AT command 'AT+ENABLE=1' to make the module enter the AT state for parameter setting. There is only this reserved word during these three minutes. After more than three minutes, you will not be able to enter AT mode; you can only send and receive data. The 'AT+ENABLE=1' command will also be sent out as data, and there are no reserved words at that time. Product Name: VHF/UHF Radio Modem RS485 Wireless Transceiver 20DBM 433MHz Transmitter and Receiver Working voltage: 4.5V-5.5V Interface: RS485 (5V GND A+ B-) Frequency: 433MHz Transmit power: -40~+20dBm Receiver sensitivity: -114dBm Operating temperature: -25°C to +75°C Transparent transmission mode baud rate: 1200, 2400, 4800, 9600 (Default), 19200 Open ground transmission distance: 500M Size (without antenna): 74 x 24 x 16mm Recommend using 2 or more units How to use (with 2 or more units): 1/2PCS: Module 1 and Module 2 send data to each other. For 3 or more units: One acts as master device, others act as slave devices. They operate similarly to a wired RS485 bus. Master device transmits data, all slave devices receive data. Any slave device transmitting data will be received by the master and other slave devices. Only one device (master or slave) is allowed to transmit data at a time. Application: IP PTZ Camera Modbus temperature sensor LED Controller RS485 Relay Remote control, remote measurement system Wireless meter Smart Home, Home Automation Color: Blue Material: Plastic + Metal Package Contents: 2 x 433M-458M VHF/UHF Radio Modem RS485 Transceiver (With shell) Only the above package content, other items not included Note: Light and different displays may cause the color of the item in the picture to differ slightly from the actual product. Measurement error allowance is +/- 1-3cm.